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Signs of Life on Mars: Microorganisms Grow at Low Pressures

Xi Yu

PureInsight | December 23, 2002

Using a unique device known as the Andromeda Chamber to simulate conditions found on Mars, University of Arkansas researchers discovered that certain microorganisms called methanogens could grow at low pressures. Their findings imply that life could have existed on the Red Planet in the past, present, or that it could do so at some point in the future. Dr. Tim Kral, an associate professor of biological sciences, presented the preliminary results at a bioastronomy conference in Australia in July. [1]

According to an electronic news report from Science Daily Magazine on August 19, 2002, "Our goal is first to get the organisms to grow well, then systematically experiment with conditions found on Mars," said Kral. They first grew test tube cultures of various methanogens in a Mars soil simulant. "Derived from altered volcanic ash, it approximates the composition, grain size, density, and magnetic properties of Martian soil. The researchers exposed the cultures to an atmosphere that consisted only of hydrogen and carbon dioxide, the raw materials methanogens need to produce energy. Methanogens release methane as a waste product, so the researchers were able to measure their growth by analyzing the amount of methane produced." [1]

"After successfully growing three different methanogens on Mars soil simulant, Kral moved on to the next step -- simulating various Martian conditions in the Andromeda Chamber." The chamber, which was originally constructed for comet simulations, is believed to be the largest instrument dedicated to space simulation research on a North American university campus. "The researchers grew methanogenic cultures in bottles and froze them." They then "replaced the atmosphere inside with an equal mixture of hydrogen and carbon dioxide at 500 millibars (about half the Earth's atmospheric pressure)." The researchers analyzed samples daily. "So far, the Andromeda Chamber studies indicate low levels of methane production. This means that the organisms are metabolizing under low pressures. Martian life would have to be able to survive at such pressures, since Mars' atmosphere is much less dense than Earth's." [1]

Do to previous discoveries about Mars surface, from the Viking Missions in 1976, most researchers believe that if life existed there it had become extinct a long time ago. However, a discovery earlier this year of large quantities of frozen water below the surface of Mars has given researchers like Kral hopes. This discovery has many scientists believing that if life exists on Mars it probably exists below the surface. Despite the fact that the Martian conditions are drastically different from those of Earth, Kral wants to continue his research and in the future he hopes to study a wide range of Mars-like conditions.

If we confine ourselves to the existing knowledge of biology discovered on Earth, it will be virtually impossible for us to make a leap forward in our exploration of other worlds and various forms of lives. Perhaps there exist lives of completely different origins at macro and microscopic levels, but if we are too confined by our ways of thinking we will be unable to recognize their existences. Take Mars for example, "Martian surface conditions include low pressure, low temperature, very little water, and an atmosphere that contains large amounts of carbon dioxide with almost no oxygen." [1] It is a harsh, inhospitable environment for any life on Earth. But is it possible that Martian lives do not require oxygen to survive? Apparently, Kral's research has already given us the answer.